I know there are a lot of other MOSS 2007 environments in this world that are waiting to be upgraded to MOSS 2010, so I hope the following will help out with your situation that took us a bit of time to fix!
- MOSS 2007 Service Pack 1 - 12.0.0.6219
- Performed an AD User Migration
- Applied Hotfix KB941422 (WSS 3.0) - which was suppose to fix the Site Data Web Service issues
- Applied all individual updates including Cumulative Updates (since SP1 and after SP2) and Service Pack 2 as per Microsoft site - http://technet.microsoft.com/en-us/office/sharepointserver/bb735839.aspx
***I have my doubts about Service Pack 2 that states that it includes all updates since SP1, therefore I updated each one individually to make sure.
If you have done the above and still get the following error for your site collection:
Error in the Site Data Web Service. (Value does not fall within the expected range.)
Then I highly recommend this blog for the fix:
http://blogs.microsoft.co.il/blogs/dorong/archive/2009/09/24/error-in-the-site-data-web-service-value-does-not-fall-within-the-expected-range.aspx
